Re: std.parallelism taskPool.map example throws exception
This appears to work ... at least, no exception: auto sm = File(fn).byLine(KeepTerminator.no) .map!a.chomp() .map!a.idup() .map!(to!double) .map!a.log10() .sum(); writeln(sum=,sm);
Re: std.parallelism taskPool.map example throws exception
This also works. auto sm = File(fn).byLineCopy() .map!a.chomp() .map!(to!double) .map!a.log10() .sum(); writeln(sum=,sm);
std.parallelism taskPool.map example throws exception
I tried to create a working example from the std.parallelism
taskPool.map code, and it throws with empty strings with length 1
being passed to to!double. Anyone have a working example? I'm
building on Windows with 2.067.1 dmd.
import std.parallelism;
import std.algorithm;
import std.stdio;
import std.conv;
import std.math;
import std.range;
import std.file;
void main()
{
auto fn = numberList.txt;
auto f = File(fn,w);
scope(exit) std.file.remove(fn);
foreach (i ; iota(10.0,2_000.0)){
f.writefln(%g,i+0.5);
}
f.close();
auto lineRange = File(fn).byLine();
auto dupedLines = std.algorithm.map!a.idup(lineRange);
auto nums = taskPool.map!(to!double)(dupedLines);
auto logs = taskPool.map!log10(nums);
double sum = 0;
foreach(elem; logs)
{
sum += elem;
}
writeln(sum=,sum);
}
Re: std.parallelism taskPool.map example throws exception
and, finally, this works using the taskPool.map, as in the
std.parallelism example. So, the trick appears to be that the
call to chomp is needed.
auto lineRange = File(fn).byLineCopy();
auto chomped = std.algorithm.map!a.chomp(lineRange);
auto nums = taskPool.map!(to!double)(chomped);
auto logs = taskPool.map!log10(nums);
double sum = 0;
foreach(elem; logs)
{
sum += elem;
}
writeln(sum=,sum);
Re: std.parallelism taskPool.map example throws exception
Unfortunately, this is not a very good example for
std.parallelism, since the measured times are better using the
std.algorithm.map calls. I know from past experience that
std.parallelism routines can work well when the work is spread
out correctly, so this example could be improved.
This is parallel
D:\visd\map\map\Releasemap
sum=1.17335e+07
time msecs:1242
Non-parallel
D:\visd\map\map\Releasemap
sum=1.17335e+07
time msecs:970
I think this example
import std.parallelism;
import std.algorithm;
import std.stdio;
import std.conv;
import std.math;
import std.range;
import std.file;
import std.datetime;
void main()
{
auto fn = numberList.txt;
auto f = File(fn,w);
scope(exit) std.file.remove(fn);
foreach (i ; iota(10.0,2_000_000.0)){
f.writefln(%g,i+0.5);
}
f.close();
std.datetime.StopWatch sw;
sw.start();
auto lineRange = File(fn).byLineCopy();
auto chomped = std.algorithm.map!a.chomp(lineRange);
auto nums = std.algorithm.map!(to!double)(chomped);
auto logs = std.algorithm.map!log10(nums);
double sum = 0;
foreach(elem; logs)
{
sum += elem;
}
long tm = sw.peek().msecs;
writeln(sum=,sum);
writeln(time msecs:, tm);
}
